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Yet another AR headspace question...

Discussion in 'General Discussion' started by ccioff, Oct 12, 2018.

  1. ccioff

    ccioff NES Member

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    Hey all,

    I've done a search and read a bunch about this... general consensus seems to be split 50/50 between "if you have quality parts, its a non-issue" and "it takes 30 seconds, always do it."

    My research on my components is inconclusive/positive-by-default. i.e., i havent heard any complaints about the components I bought, even though they are on the 'budget' side of the spectrum.

    my question is two-fold.

    1. My BCG is a PSA Freedom complete BCG, and my barrel is Ballistic Advantage:

    PSA Freedom 5.56mm Tested Full Auto Bolt Carrier Group - 507608

    Ballistic Advantage Modern Series 14.7" 5.56 NATO Lightweight Contour 1:7 Nitride AR-15 Barrel - Mid-Length - 1/2x28 BABL556012M

    Are these considered by most of you to be 'quality' and 'free of known issues?'

    2. Shot in the dark, but anyone in the woburn area going to be at MassRifle tonight have a go/no-go gauge set they might want to bring to the club with them and let me use for those 30 seconds?

    Thanks all.
     

  2. mac1911

    mac1911 NES Member

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    A local shop or Smith could do it.
     
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  3. amm5061

    amm5061 NES Member

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    This. Just take it into your local gunsmith's shop.
     
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  4. ccioff

    ccioff NES Member

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    eh. I'd rather buy my own gauges. (maybe thats the real answer to my question) I'm a machinist and I like doing things for myself. Plus the closest shop to me told me that they refuse to pin/weld my muzzle device (lantac dragon) and im doing that myself. left a bad taste in my mouth.
     
  5. Mesatchornug

    Mesatchornug

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    Not a member at MassRifle, but I have gauges. I'd be happy to meet up this afternoon.
     
    Last edited: Oct 12, 2018
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  6. Lsgun1

    Lsgun1

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    Its smarter to do it but I'm sure its fine. Proceed at your own risk.
     
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  7. tripletaco

    tripletaco NES Member

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    Someone feel free to correct me if Im wrong. I did my own research on this recently and heres why I think the answer you often hear on the internet is "dont worry it'll be fine".

    Standard min and max chamber length as measured from a datum point on the shoulder to the bolt face is 1.4596" to 1.4636". So thats .004", not a totally trivial tolerance but also nothing really that crazy in terms of machining. Then, consider that a field gauge will pass a chamber of up to 1.4736". So thats a .010" range where a gun will be safe to shoot.
     
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  8. larueminati

    larueminati

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    The headspace is set by the barrel maker when they pinned the extension to the barrel. If you have a barrel from a reputable company I wouldn't worry about it.

    You can't adjust it.
     
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  9. Mesatchornug

    Mesatchornug

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    You can't adjust it, but you can get them to RMA it. While it's unlikely that the parts are wrong, it happens.

    In fact, I'm rebuilding a prototype for a client today because my "reputable" manufacturer bored a hole 0.011" undersized, and my other parts don't fit. The rest of the parts were fine, but somehow their "infallible" robots cocked this one up.
     
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  10. TomMontana

    TomMontana NES Member

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    I think my set of Go and No Go gauges cost $60. One of those piece of mind expenses that may not be needed. But if things go wrong, you may be kicking yourself for not checking it beforehand. Good luck.
     
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  11. xtry51

    xtry51 NES Member

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    PSA has some crap BCGs out there. I've posted a few times about a couple I own. They're fine for toys, but I would definitely headspace anything with a PSA part and not trust your life to it. 2 of the 3 BCGs I have from them are unreliable. Frequent FTFs. Great for training though and it's hard to beat the process they sell some uppers at.

    If you want a quality BCG buy a BCM.
     
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  12. ccioff

    ccioff NES Member

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    Thanks for the input everyone who replied. Shout out to username Mesatchornug who lent me a gauge set. The bolt closed on the go and didn't close on the no go. So I went to the range. Put 60 rounds through it, no issues. Other than my sights seemingly moving everywhere.

    If I was gonna have an issue, I'd know about it by now, right?

    Going to upgrade my bcg soon ish.

    Thanks
     
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  13. Squib308

    Squib308

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    if you're building your own uppers then invest in a no-go and field gauge. the "go" gauge is semi pointless as any factory brass can do the same but i think amazon or wherever has the 3 gauge sets worth the $$ no doubt. it's unlikely that one is going to find a barrel with excessive headspace although theoretically possible. better to find this before going to the range. if one has a few extra BCG's laying around then can tease out whether the issue is bolt or barrel extension.

    at the same time there are many folk out there who have built countless uppers without ever checking headspace...and they've never had an issue so one could make this argument just as well.

    unrelated topic but I have watched people drop their bolt onto a field gauge and it makes me absolutely cringe. i'm like WTF why wouldn't you just manually push the bolt forward with normal amount of pressure. don't drop the damn bolt on it!

    i agree w above about getting a quality BCG. in terms of reliability, the gas system and BCG are critical. the $60 or so saved on a budget BCG just isn't worth it. while the BCM BCGs are excellent, in full disclosure I did once receive a BCM BCG from Aim that had a bent gas key. the gas key was unable to fit over the gas tube so it would not fit into the upper. of course Aim replaced it no questions asked but I was surprised that BCM shipped out a totally defective BCG. it shows that no matter how great a company they're still human.
     
    Last edited: Oct 13, 2018
  14. Bonesinium

    Bonesinium NES Member

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    Neither BCM nor PSA manufacture their own bolts and carriers. They many even be manufactured by the same company. I haven’t heard anything bad about the PSA premium BCG’s.
     
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  15. Artie

    Artie NES Member

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    per the Internet a couple years ago, PSA's Premium were Toolcraft carriers and FN bolts. My 1st BCG was a BCM which after the fact i found out, per the Internet, one of their vendors is FN too.
     
  16. xtry51

    xtry51 NES Member

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    Can't tell you who makes them. I can tell you they do look different and they certainly measure different. I have a thread a while back I posted dimensions in. The PSA was out of spec in at least 3 dims.

    I've never had a FTF with a BCM and I have a lot of them. I have a handful of PSA and only 1 of them has operated without malfunction. YMMV.
     
  17. Bonesinium

    Bonesinium NES Member

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    I have been using a PSA premium BCG for the past two years almost exclusively and have had exactly zero stoppages of any kind. That includes 16 local 3-Gun matches in addition to regular range use.

    I’m sure there are some from them that are bad. Same goes for other manufactures. And since both BCM and PSA source them for other manufacturers, and I’ve also heard of bad BCM bolts and carriers, I doubt in general you are going to have any better or worse luck with BCM over PSA, and definitely not for twice the price.
     
  18. groundscrapers

    groundscrapers NES Member

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    The way many people I know check is to start with a go gauge and make sure it goes into battery on that. Next, add a piece of scotch tape to the back side which will put it to your no-go and make sure it won't close on that and you should be good to go. Field max is pointless. If I get a factory barrel and it takes a no go im sending it back before I bother trying to fit a field max.
     
  19. frenchman

    frenchman NES Member

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    There are many reliable BCGs out there right now. Up there are certainly BCM, Fail Zero, LMT, Odin Works and a few others. I'd put the PSA in the same category as Bear Creek, Anderson and others. I've heard good things about the BCGs from AIM surplus. Not good enough to switch one out for my BCM or Fail Zero, but good enough to pick one over a PSA freedom. I own a PSA premium that runs fine when wet, but struggles when not lubed enough. Can't say the same thing about the other two. Actually, I plan on putting the FZ in the place of the PSA and getting another BCM for my new build.
     

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